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991.
全液压转向系统的关键部件是由转向阀与计量马达组成的液压转向器,相关部件都是圆周对称部件,外表都是精密加工表面,制造时无法在零件表面刻上安装记号,极易装配错误而造成方向盘发生严重的打颤现象而不能正常工作,甚至会造成人身安全事故。本文通过CAD软件作图,根据其工作原理论述各部件之间的配流装配关系,并通过试车验证,给全液压转向器的正确装配起到明确的指导作用。 相似文献
992.
993.
优质籼稻不育系95A的选育 总被引:1,自引:2,他引:1
95A是用95占为父本、珍汕97A为母本杂交,再连续回交选育成的野败型不育系,不育性稳定,株叶型和粒型好,分蘖力强,有效穗多,穗长粒多,米质好,抗性好,柱头外露率高,异交结实率高,易于繁殖、制种。1996年7月通过技术鉴定。 相似文献
994.
作为中国科学院可持续发展战略研究组组长、首席科学家,同时又有着中国科学院中美环境与可持续发展委员会的中方主席、中国国家高技术计划软科学研究战略组组长、中国科学院科技政策研究所学术委员会副主任等一系列头衔的牛文元教授,当选了第二届环境大使的候选人。对于这样一位候选人,无论什么方式的描述都已经显得多余,现就将大家共同关心的牛教授的采访记录如实呈现,以飨读者。 相似文献
995.
为解决水稻直播出苗难、成苗率低、秧苗素质差、病虫危害重等技术难点,采用高吸水种衣剂进行种子包衣,研究其在旱直播水稻上的应用效应。结果表明:包衣处理可提高旱直播水稻出苗率、成苗率,提高秧苗素质,减轻病虫危害,增加产量。与未包衣对照相比,包衣处理的出苗率提高13.5%,成苗率提高18.2%,恶苗病、稻蓟马、麻雀、老鼠、干尖线虫等病虫害分别减轻90.5%、94.3%、95.3%、88.2%、89.5%,株高降低,秧苗单株带蘖数、假茎粗、总根数、百苗干重明显增加,各主要生育期茎蘖数多、叶面积指数高,干物质积累量高,增产显著。应用高吸水种衣剂进行种子包衣,可解决直播水稻目前存在的主要技术难点,促进水稻直播技术的发展。 相似文献
996.
Wagner BA Salman MD Dargatz DA Morley PS Wittum TE Keefe TJ 《Preventive veterinary medicine》2003,57(3):127-139
Factor analysis was used to assess relationships in the minimum-inhibitory concentration among 17 antimicrobials tested on isolates of Escherichia coli isolated from 360 faecal samples obtained from feedlot cattle. Six factors were extracted using maximum-likelihood factor analysis. The factors were interpretable antimicrobial groupings based on class of antimicrobial and previously described associations. New-generation cephalosporins, older-generation beta-lactams, fluoroquinolones and aminoglycosides grouped separately as classes of antimicrobials on four of the six factors. One of the remaining factors was a grouping of antimicrobials that had been identified as being related in previous feedlot studies. The last factor was a grouping of three of the five antimicrobials that comprise the antimicrobials found in penta-resistant strains of Salmonella Typhimurium. The factor analysis described patterns in the MIC data that would not have been apparent if only antimicrobial-resistance data categorized as susceptible-resistance had been analysed. 相似文献
997.
陈超君 《广西农业生物科学》1998,(Z1)
用不同浓度的MgSO4、KH2PO4、Ca(OH)2混合叶面肥喷施宿根甘蔗,结果表明:(1)在伸长期甘蔗的硝酸还原酶的活性增强,使甘蔗植株吸收的硝态氮能尽快转化为还原型,促进氨基酸的合成,有利于甘蔗的生长;进入伸长末期,甘蔗的硝酸还原酶活性比CK弱,抑制氮素吸收转化,有利于甘蔗工艺成熟。(2)喷施40d以后,能明显增加甘蔗叶片的叶绿素含量,从而提高光合作用强度。(3)收获时甘蔗的产量和品质都有不同程度的提高。 相似文献
998.
Patrícia A. B. Barreto Emanuela F. Gama-Rodrigues A. C. Gama-Rodrigues Alexandre G. Fontes José C. Polidoro Maria Kellen S. Moço Regina C. R. Machado V. C. Baligar 《Agroforestry Systems》2011,81(3):213-220
Agroforestry systems can play a major role in the sequestration of carbon (C) because of their higher input of organic material
to the soil. The importance of organic carbon to the physical, chemical, and biological aspects of soil quality is well recognized.
However, total organic carbon measurements might not be sensitive indicators of changes in soil quality. Adoption of procedures
that can extract the more labile fraction preferentially might be a more useful approach for the characterization of soil
organic carbon resulting from different soils. This study aimed to evaluate organic carbon (C) fractions distribution in different
soil layers up to 50 cm depth in two soil orders under cacao (Theobroma
cacao) agroforestry systems (AFS) in Bahia, Brazil. Soil samples were collected from four depth classes (0–5, 5–10, 10–30 and 30–50 cm)
under two cacao agroforestry systems (30-year-old stands of cacao with Erythrina glauca, as shade trees) in Latosol and Cambisol, in Bahia, Brazil. The determination of oxidizable carbon by a modified Walkley–Black
method was done to obtain four C fractions with different labile forms of C (fraction 1: labile fraction; fraction 2: moderate
labile fraction; fraction 3: low labile fraction and fraction 4: recalcitrant fraction). Overall, at two cacao AFS, the C
fractions generally declined with increase in soil depth. The C fractions 1 and 2 were 50% higher on upper layers (0–5 and
5–10 cm). More than 50% of organic C was found in more labile fraction (fraction 1) in all depths for both soils. High value
of C fraction 1 (more labile C)-to-total organic C ratio was obtained (around 54–59%, on Latosol and Cambisol, respectively),
indicating large input of organic matter in these soils. 相似文献
999.
1000.
Dan LU Shengzhe SHANG Shen LIU Ying WU Fangfang WU Tan TAN Qiuyan LI Yunping DAI Xiaoxiang HU Yaofeng ZHAO Ning LI 《农业科学与工程前沿(英文版)》2014,1(3):179
Butyrylcholinesterase (BCHE) is a natural bioscavenger that protects humans against organophosphate toxicity. Due to the limited yield of human BCHE (hBCHE) when purifying from human plasma, it is necessary to find an alternative method to produce this protein. One potential method is to produce transgenic livestock that make modified milk containing high concentration of hBCHE. In this study, we cloned the hBCHEgene into a human lactoferrin (hLF) bacterial artificial chromosome (BAC) construct to make a hLF-hBCHE BAC construct. Subsequently, we injected the BAC construct into pronuclei of mouse fertilized embryos and generated transgenic mice. Expression analysis showed that recombinant hBCHE (rhBCHE) was expressed efficiently in the mammary gland of the transgenic mice and the concentration of rhBCHE in the milk of individual mice ranged from 76±12 to 159±28 mg·L-1. Protein function tests showed that rhBCHE has the same enzymatic activity as the native hBCHE. Our results pave the way for making transgenic livestock to produce large quantities of rhBCHE. 相似文献